A complete guide to the use of water-based shoe paint wetting agents: a scientific guide from
preparation to practice
In the process of shoe manufacturing, the widespread use of water-based shoe paint has promoted the environmental
protection process of the industry. However, in order to obtain the ideal coating effect, the correct use of water-based
shoe paint wetting agents is crucial. From preliminary preparation to specific operation, every link affects the final coating
quality. Next, this article will introduce the use of water-based shoe paint wetting agents in detail.
I. Full preparation before use
1. In-depth understanding of the characteristics of shoe materials and coatings
Before using water-based shoe paint wetting agents, you need to have a comprehensive understanding of shoe materials and
coatings. There are many types of shoe materials, and the surface properties of leather, fabrics, synthetic materials (such as TPU,
PVC) are significantly different. For example, the leather surface has natural texture and oil residue, the fabric fibers are loose and
porous, and the synthetic material surface is smooth and has low surface energy. These characteristics determine the different
needs for wetting agents.
At the same time, it is necessary to clarify the type of water-based shoe paint, such as acrylates, polyurethanes, etc. Different types
of coatings have different compatibility with wetting agents. Acrylic water-based shoe paints may work better with non-ionic
wetting agents, while polyurethane coatings may be more suitable for anionic wetting agents with specific structures. Only by fully
understanding the characteristics of both can we lay the foundation for the subsequent selection of suitable wetting agents.
2. Accurate selection of wetting agent type
According to the characteristics of shoe materials and coatings, accurate selection of wetting agent type is the key. Common water-based
shoe paint wetting agents include anionic, cationic, nonionic and zwitterionic.
Anionic wetting agent: suitable for hydrophilic shoe materials, such as cotton and linen fabrics. It can effectively reduce the surface tension
of the coating and spread quickly on the hydrophilic surface, but in a hard water environment or when coexisting with cationic substances,
precipitation or performance degradation may occur. Environmental conditions must be carefully evaluated when using it.
Cationic wetting agent:
It has unique advantages for some special synthetic shoe materials with negative charges, and can enhance adsorption and wetting effects
through electrostatic effects. However, mixing with anionic coatings or additives may cause reactions, and strict attention should be paid
to formula compatibility.
Non-ionic wetting agent:
With good chemical stability and wide compatibility, it has become one of the most widely used types. It is not affected by pH value and
hard water, and also has a certain defoaming function. It is suitable for most water-based shoe paint systems, especially for production
scenarios with high stability requirements.
Zwitterionic wetting agent:
It exhibits different ionic properties under different pH environments and can adapt to a variety of complex shoe surfaces and coating
systems, but because of its high synthesis cost, it is currently mostly used for high-end or special shoe coating.
3. Scientifically determine the amount of addition
The amount of wetting agent added has a significant impact on the coating effect, usually between 0.1% and 2% of the total amount of
water-based shoe paint, but the specific value needs to be determined through experiments. You can prepare multiple groups of the same
water-based shoe paint samples, add different proportions of wetting agents to each, and conduct coating tests on small samples of the
same type of shoe. Observe the coating's spreadability, the presence of shrinkage cavities or flow marks, the coating's flatness and adhesion,
and other indicators. For example, first add in gradients of 0.3%, 0.6%, 0.9%, etc., compare the coating effects at different addition amounts,
and select the addition ratio that can achieve the best effect and reasonable cost. At the same time, it should be noted that excessive
addition may lead to abnormal coating performance, such as slower drying speed and reduced coating water resistance.
II. Standardized addition operation process
1. Necessary dilution treatment
For some high-concentration or high-viscosity wetting agents, dilution operations help them to be evenly dispersed in the coating.
According to the wetting agent product instructions, select a suitable diluent, generally deionized water or a solvent in the coating system.
Dilution is carried out in accordance with the prescribed ratio, such as mixing 1 part of wetting agent with 9 parts of diluent, and using a
clean stirring device to fully stir evenly to ensure the formation of a uniform dilution solution. It should be noted that during the dilution
process, safety regulations must be strictly followed, and operations must be carried out in a well-ventilated environment to avoid inhalation
of volatile gases.
2. Accurate adding steps
In the production process of water-based shoe paint, wetting agent is usually added in the paint mixing stage. Adjust the stirring equipment
to low speed to avoid a large number of bubbles generated by high-speed stirring. Slowly pour the diluted wetting agent solution or
undiluted wetting agent along the inner wall of the mixing barrel and continue stirring for 15-20 minutes to fully integrate the wetting agent
into the paint system. During the stirring process, the speed can be appropriately increased to promote the dispersion of the wetting agent,
but it is necessary to prevent the paint from splashing or generating too many bubbles due to too fast a speed. After the addition is
completed, continue stirring for 5-10 minutes to ensure that the paint is evenly mixed.
3. Mixing effect inspection
After adding the wetting agent and stirring, the mixing effect of the paint needs to be checked. Observe whether the paint surface is flat,
whether there are floating objects or precipitation, take a small amount of paint for coating test, and check its spreadability and leveling on
the surface of the shoe material. If the paint is found to be uneven, such as local particles or inconsistent colors, it is necessary to continue
stirring until it is uniform; if a large number of bubbles appear, it can be left to stand for a period of time to allow the bubbles to be
discharged naturally, or add an appropriate amount of defoaming agent for treatment.
III. Key points and precautions during use
1. Pretreatment of shoe materials cannot be ignored
Before using the wetting agent, the shoe materials must be fully pretreated. Leather shoes need to remove grease, dust and impurities
on the surface. They can be cleaned and dried with special detergents; fabric shoes need to be degreased and dusted; synthetic shoes
need to be surface polished or corona treated to increase surface roughness and activity and improve paint adhesion. If the surface of
the shoe material is not properly treated, it is difficult to obtain the ideal coating effect even if a wetting agent is used.
2. Pay attention to compatibility with other additives
Water-based shoe paints usually contain a variety of additives, such as defoamers, thickeners, leveling agents, etc. When using a wetting
agent, ensure that it is compatible with other additives. Before large-scale production, conduct a small test experiment to mix the
wetting agent with other additives according to the formula ratio to observe whether adverse reactions such as flocculation,
stratification, and discoloration occur. If there is a compatibility problem, it is necessary to adjust the type of additives or the order of
addition, and replace it with a more suitable wetting agent product if necessary.
3. Strictly control storage conditions
The storage conditions of wetting agents directly affect their performance. They should be placed in a cool, dry, and ventilated warehouse,
away from direct sunlight and high temperature environment, and the storage temperature is generally controlled between 5℃ - 35℃.
At the same time, keep away from fire sources and oxidants to prevent safety accidents. Different types of wetting agents should be stored
separately to avoid mutual contamination. Check the packaging regularly to see if it is intact. If the packaging is damaged or leaking, handle
it in time to prevent the wetting agent from deteriorating.
4. Take safety precautions
Although most water-based shoe paint wetting agents are environmentally friendly products, safety precautions are still required during use.
Operators should wear protective gloves, masks and goggles to prevent wetting agents from contacting the skin and eyes. If accidentally
contacted, immediately rinse with plenty of water for more than 15 minutes and seek medical attention in time. Equip the necessary
fire-fighting equipment and emergency flushing equipment at the place of use to ensure production safety.
Mastering the correct use of water-based shoe paint wetting agents can give full play to their performance advantages and achieve
high-quality shoe coating effects. Every step from preliminary preparation to actual operation requires rigor and meticulousness to ensure
the quality of footwear products and the smooth progress of production.
